diff --git a/db/migrate/20260113140000_change_captain_unit_id_null_in_captain_inboxes.rb b/db/migrate/20260113140000_change_captain_unit_id_null_in_captain_inboxes.rb
deleted file mode 100644
index 1d6110f..0000000
--- a/db/migrate/20260113140000_change_captain_unit_id_null_in_captain_inboxes.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-class ChangeCaptainUnitIdNullInCaptainInboxes < ActiveRecord::Migration[7.0]
-  def change
-    change_column_null :captain_inboxes, :captain_unit_id, true
-  end
-end
diff --git a/db/migrate/20260114101010_add_unit_to_captain_inboxes.rb b/db/migrate/20260114101010_add_unit_to_captain_inboxes.rb
index 89bfcef..67f6c77 100644
--- a/db/migrate/20260114101010_add_unit_to_captain_inboxes.rb
+++ b/db/migrate/20260114101010_add_unit_to_captain_inboxes.rb
@@ -1,5 +1,5 @@
 class AddUnitToCaptainInboxes < ActiveRecord::Migration[7.1]
   def change
-    add_reference :captain_inboxes, :captain_unit, null: false, foreign_key: true
+    add_reference :captain_inboxes, :captain_unit, null: true, foreign_key: true
   end
 end